HT1621

Rev. 2.60

14

October 28, 2009

PATENTED

Name

ID

Command Code

D/C

Function

Def.

TONE OFF

100

0000-1000-X

C

Turn off tone outputs

Yes

TONE ON

100

0000-1001-X

C

Turn on tone outputs

CLR TIMER

100

0000-11XX-X

C

Clear the contents of time base generator

CLR WDT

100

0000-111X-X

C

Clear the contents of WDT stage

XTAL 32K

100

0001-01XX-X

C

System clock source, crystal oscillator

RC 256K

100

0001-10XX-X

C

System clock source, on-chip RC oscillator

Yes

EXT 256K

100

0001-11XX-X

C

System clock source, external clock source

BIAS 1/2

100

0010-abX0-X

C

LCD 1/2 bias option

ab=00: 2 commons option

ab=01: 3 commons option

ab=10: 4 commons option

BIAS 1/3

100

0010-abX1-X

C

LCD 1/3 bias option

ab=00: 2 commons option

ab=01: 3 commons option

ab=10: 4 commons option

TONE 4K

100

010X-XXXX-X

C

Tone frequency, 4kHz

TONE 2K

100

011X-XXXX-X

C

Tone frequency, 2kHz

IRQ DIS

100

100X-0XXX-X

C

Disable IRQ output

Yes

IRQ EN

100

100X-1XXX-X

C

Enable IRQ output

F1

100

101X-X000-X

C

Time base/WDT clock output:1Hz

The WDT time-out flag after: 4s

F2

100

101X-X001-X

C

Time base/WDT clock output:2Hz

The WDT time-out flag after: 2s

F4

100

101X-X010-X

C

Time base/WDT clock output:4Hz

The WDT time-out flag after: 1s

F8

100

101X-X011-X

C

Time base/WDT clock output:8Hz

The WDT time-out flag after: 1/2s

F16

100

101X-X100-X

C

Time base/WDT clock output:16Hz

The WDT time-out flag after: 1/4s

F32

100

101X-X101-X

C

Time base/WDT clock output:32Hz

The WDT time-out flag after: 1/8s

F64

100

101X-X110-X

C

Time base/WDT clock output:64Hz

The WDT time-out flag after: 1/16s

F128

100

101X-X111-X

C

Time base/WDT clock output:128Hz

The WDT time-out flag after: 1/32s

Yes

TEST

100

1110-0000-X

C

Test mode, user don

¢t use.

NORMAL

100

1110-0011-X

C

Normal mode

Yes

Note:

X : Don

A5~A0 : RAM addresses

D3~D0 : RAM data

D/C : Data/command mode

Def. : Power on reset default

All the bold forms, namely 110, 101, and 100, are mode commands. Of these, 100 indicates the command

mode ID. If successive commands have been issued, the command mode ID except for the first command will

be omitted. The source of the tone frequency and of the time base/WDT clock frequency can be derived from

an on-chip 256kHz RC oscillator, a 32.768kHz crystal oscillator, or an external 256kHz clock. Calculation of the

frequency is based on the system frequency sources as stated above. It is recommended that the host control-

ler should initialize the HT1621 after power on reset, for power on reset may fail, which in turn leads to the mal-

functioning of the HT1621.